In 3rd Generation Partnership Project (3GPP) that is a mobile communication system standardization project, a Multimedia Broadcast Multicast Service (MBMS) has been established (see Non-Patent Literature 1). In the MBMS, a plurality of user terminals receives an MBMS service that is provided from a network in a multicast or broadcast manner. For example, the MBMS service is a broadcast video delivery.
In 3GPP, standardization for newly introducing a group communication function is scheduled to be conducted in Release 12. For example, the group communication is a group call (voice over Internet protocol (VoIP)) based on packet communication. In the group communication, basically, unicasting is applied to uplink communication, and unicasting or multicasting is applied to downlink communication.